I just bought a fenrir for my son's 920 setup and at first i was getting outrageous temps with MX-3 i tried several mounts and each time i removed the Fenrir it was as if the cooler was allergic to TIM as it has spread almost totally off the CPU and HS
I used Artic Silver cleaning AND surface purifier, as the cleaner should just be alcohol i would have though this would have evaporated away by the time i mounted but not sure about the purifier so i tried without using that
I got satisfactory results by first spreading a thin film ( yes my MX-3 spreads easily) over the HS then with a very small amount of residue that was left on my spreader i "bloomed" the CPU so it had just a dull covering of TIM
I then put a fair sized blob of TIM on the CPU, the size of this is tricky to describe but a medium sizes unfrozen garden pea size !!! ( Is that the African swallow or the European swallow ?)